The Invention Relates to Fluid Temperature Measurement.
In fluid carrying pipelines it is advantageous to determine if fluid leakage is occurring and to determine the amount of leakage. In gas pipelines for example it is desirable to be able to measure any leakage, which can be of a very small magnitude, over a pipeline of several kilometres.
Typically the test involves applying air to an empty pipeline at a pressure of 1.5 times the maximum working pressure of the gas main. The pressure is then monitored over several days or more to see if any pressure drop occurs during this period. If a pressure drop reading indicative of leakage of more than 0.0028 scmh (0.1 scfh) is established, then further investigation is indicated in order to determine the source of leak. In practice the pressure drop may not only occur as a result of leaks, but may vary due to temperature and pipe volume changes. This is particularly true for long pipelines where the pressure drop may be so small that the test period has to be extended over several weeks.
To provide a more effective pressure test it would also be necessary to determine the pipe volume changes over such a long period and the temperature changes in the fluid.
The volume may change in polyethylene pipes due to creep and a mechanism for dealing with creep is the subject of our earlier patent application.
The present invention is concerned with temperature aspects.
According to the invention there is provided a fluid temperature measurement system comprising:
transducer means for generating an acoustic signal for passage through the fluid; detector means for detecting a first signal as the acoustic signal passes through the fluid to a first position; detector means for detecting a second signal as the acoustic signal passes through the fluid to a second position; and
processor means for calculating temperature as a result of information derived from the first and second detected signals.
Further according to the invention there is provided a method of temperature measurement in a fluid comprising:
generating an acoustic signal for passage through the fluid; detecting a first signal as the acoustic signal passes through the fluid to a first position; detecting a second signal as the acoustic signal passes through the fluid to a second position: and calculating temperature as a result of information derived from the first and second detected signals.
Still further according to the invention there is provided a pipe leak measurement apparatus comprising: means for detecting fluid pressure within a pipe over a selected period, means for measuring the temperature of the fluid with the pipe over a selected time period, and means for compensating for temperature changes of the fluid to provide a corrected fluid pressure measurement over the selected period to indicate the degree of pressure loss that would have occurred during the selected time period if temperature did not vary.
Still further according to the invention there is provided a method of pipe leak measurement comprising: applying a source of pressure to the sealed pipe, detecting fluid pressure within the pipe over a selected period, measuring the temperature of the fluid within the pipe over a selected time period, and compensating for temperature changes of the fluid to provide a corrected fluid pressure measurement over the selected period to indicate the degree of pressure loss which would have occurred if temperature had remained constant during the selected time period.